JEE Questions for Physics Wave Optics Quiz 10 - MCQExams.com

Figure here shows P and Q as two equally intense coherent sources emitting radiations of wavelength 20 m. The separation PQ is 5.0 m and phase of P is ahead of the phase of Q by 90°. A, B and C are three distant points of observation equidistant from the mid-point of PQ. The intensity of radiations at A, B, C will bear the ratio
Physics-Wave Optics-95720.png
  • 0 : 1 : 4
  • 4 : 1 : 0
  • 0 : 1 : 2
  • 2 : 1 : 0
In Young\'s double slit experiment, the intensity on the screen at a point where path difference λ is K. What will be the intensity at the point where path difference is λ / 4

  • Physics-Wave Optics-95722.png
  • 2)
    Physics-Wave Optics-95723.png
  • K
  • Zero
When one of the slits of Young\'s experiment is covered with a transparent sheet of thickness 4.8 mm, the central fringe shifts to a position originally occupied by the 30th bright fringe. What should be the thickness of the sheet if the central fringe has to shift to the position occupied by 20th bright fringe
  • 3.8 mm
  • 1.6 mm
  • 7.6 mm
  • 3.2 mm
In the ideal double-slit experiment, when a glass-plate (refractive index 1.of thickness t is introduced in the path of one of the interfering beams (wavelength λ), the intensity at the position where the central maximum occurred previously remains unchanged. The minimum thickness of the glass-plate is

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  • 2)
    Physics-Wave Optics-95727.png

  • Physics-Wave Optics-95728.png

  • Physics-Wave Optics-95729.png
The time period of rotation of the sun is 25 days and its radius is 7 × 108 m. The Doppler shift for the light of wavelength 6000 Å emitted from the surface of the sun will be
  • 0.04 Å
  • 0.40 Å
  • 3.3 Å
  • 33 Å
In hydrogen spectrum the wavelength of Hα line is 656 nm whereas in the spectrum of a distant galaxy, Hα line wavelength is 706 nm. Estimated speed of the galaxy with respect to earth is
  • 2 × 108 m/s
  • 2 × 107 m/s
  • 2 × 106 m/s
  • 2 × 105 m/s
The periodic time of rotation of a certain star is 22 days and its radius is 7 × 108 metres. if the wavelength of light emitted by its surface be 4320 Å, the Doppler shift will be (1 day = 86400 sec)
  • 0.033 Å
  • 0.33 Å
  • 3.3 Å
  • 33 Å
In a two slit experiment with monochromatic light fringes are obtained on a screen placed at some distance from the sits. If the screen is moved by 5 × 10–2 m towards the slits, the change in fringe width is 3 × 10–5 m. If separation between the slits is 10–3 m, the wavelength of light used is
  • 6000 Å
  • 5000 Å
  • 3000 Å
  • 4500 Å
In the figure is shown Young\'s double slit experiment. Q is the position of the first bright fringe on the right side of O. P is the 11th fringe on the other side, as measured from Q. If the wavelength of the light used is 600 × 10–10 m, then S1B will be equal to
Physics-Wave Optics-95735.png
  • 6 × 10–6m
  • 6.6 × 10–6m
  • 3.138 × 10–7m
  • 3.144 × 10–7m
Four light waves are represented by
(i) y = a1 sin ω t
(ii) y = a2 sin (ω t + ϕ)
(iii)y = a1 sin 2ω t
(iv) y = a2 sin2 (ω t + ϕ)
Interference fringes may be observed due to superposition of
  • (i) and (ii)
  • (i) and (iii)
  • (ii) and (iv)
  • (iii) and (iv)
In Young\'s double slit experiment the y-co-ordinates of central maxima and 10th maxima are 2 cm and 5 cm respectively. When the YDSE apparatus is immersed in a liquid of refractive index 1.5 the corresponding y-co-ordinates will be
  • 2 cm, 7.5 cm
  • 3 cm, 6 cm
  • 2 cm, 4 cm
  • 4/3 cm, 10/3 cm
The maximum intensity in Young\'s double slit experiment is I0. Distance between the slits is d = 5λ, where λ is the wavelength of monochromatic light used in the experiment. What will be the intensity of light in front of one of the slit on a screen at a distance D =10 d

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  • 2)
    Physics-Wave Optics-95739.png

  • Physics-Wave Optics-95740.png

  • Physics-Wave Optics-95741.png
A point source of electromagnetic radiation has an average power output of 800 W. The maximum value of electric field at a distance 4.0 m from the source is
  • 64.7 V/m
  • 57.8 V/m
  • 56.72 V/m
  • 54.77 V/m
A monochromatic beam of light falls on YDSE apparatus at some angle (say θ) as shown in figure. A thin sheet of glass in inserted in front of the lower slit S2. The central bright fringe (path difference =will be obtained
Physics-Wave Optics-95743.png
  • At O
  • Above O
  • Below O
  • Anywhere depending on angle θ, thickness of plate t and refractive of glass µ
In Young\'s double slit experiment how many maximas can be obtained on a screen (including the central maximum) on both sides of the central fringe if λ = 2000 Å and d= 7000 Å
  • 12
  • 7
  • 18
  • 4
In a Young\'s double slit experiment, the slits are 2 mm apart and are illuminated with a mixture of two wavelengths λ0 = 750 nm and λ = 900 nm. The minimum distance from the common central bright fringe on a screen 2 m from the slits where a bright fringe from one interference pattern coincides with a bright fringe from the other is
  • 1.5 mm
  • 3 mm
  • 4.5 mm
  • 6 mm
A flake of glass (refractive index 1.is placed over one of the openings of a double slit apparatus. The interference pattern displaces itself through seven successive maxima towards the side where the flake is placed. If wavelength of the diffracted light is λ = 600 nm, then the thickness of the flake is
  • 2100 nm
  • 4200 nm
  • 8400 nm
  • None of these
Two ideal slits S1 and S2 are at a distance d apart, and illuminated by light of wavelength λ passing through an ideal source slit S placed on the line through S2 as shown. The distance between the planes of slits and the source slit is D. A screen is held at a distance D from the plane of the slits. The minimum value of d for which darkness at O is
Physics-Wave Optics-95748.png

  • Physics-Wave Optics-95749.png
  • 2)
    Physics-Wave Optics-95750.png

  • Physics-Wave Optics-95751.png

  • Physics-Wave Optics-95752.png
In a double slit arrangement fringes are produced using light of wavelength 4800 Å. One slit is covered by a thin plate of glass of refractive index 1.4 and the other with another glass plate of same thickness but of refractive index 1.7. By doing so the central bright shifts to original fifth bright fringe from centre. Thickness of glass plate is
  • 8µm
  • 6µm
  • 4µm
  • 10µm
Two point sources X and Y emit waves of same frequency and speed but Y lags in phase behind X by 2πl radian. If there is a maximum in direction D the distance XO using n as an integer is given by
Physics-Wave Optics-95755.png

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  • 2)
    Physics-Wave Optics-95757.png

  • Physics-Wave Optics-95758.png

  • Physics-Wave Optics-95759.png
A beam with wavelength λ falls on a stack of partially reflecting planes with separation d. The angle θ that the beam should make with the planes so that the beams reflected from successive planes may interfere constructively is (where n = 1, 2……)
Physics-Wave Optics-95761.png

  • Physics-Wave Optics-95762.png
  • 2)
    Physics-Wave Optics-95763.png

  • Physics-Wave Optics-95764.png

  • Physics-Wave Optics-95765.png
Two coherent sources separated by distance d are radiating in phase having wavelength λ. A detector moves in a big circle around the two sources in the plane of the two sources. The angular position of n = 4 interference maxima is
Physics-Wave Optics-95767.png

  • Physics-Wave Optics-95768.png
  • 2)
    Physics-Wave Optics-95769.png

  • Physics-Wave Optics-95770.png

  • Physics-Wave Optics-95771.png
Two coherent sources S1 and S2 are separated by a distance four times wavelength λ of the source. The sources lies along y axis whereas a detector moves along + x axis. Leaving the origin and far off points the number of points where maxima are observe is
  • 2
  • 3
  • 4
  • 5
A circular disc is placed in front of a narrow source. When the point of observation is at a distance of 1 meter from the disc, then the disc covers first HPZ. The intensity at this point is I0 The intensity at a point distance 25 cm from the disc will be (If ratio of consecutive amplitude of HPZ is 0.9)
  • I1 = 0.531I0
  • I1 = 0.053 I0
  • I1 = 53 I0
  • I1 = 5.03 I0
A wavefront presents one, two and three HPZ at points A, B and C respectively. If the ratio of consecutive amplitudes of HPZ is 4 : 3, then the ratio of resultant intensities at these point will be
  • 169 : 16 : 256
  • 256 : 16 : 169
  • 256 : 16 : 196
  • 256 : 196 : 16
A circular disc is placed in front of a narrow source. When the point of observation is 2 m from the disc, then it covers first HPZ. The intensity at this point is I. When the point of observation is 25 cm from the disc then intensity will be

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  • 2)
    Physics-Wave Optics-95777.png

  • Physics-Wave Optics-95778.png

  • Physics-Wave Optics-95779.png
In a single slit diffraction of light of wavelength λ by a slit of width e, the size of the central maximum on a screen at a distance b is

  • Physics-Wave Optics-95781.png
  • 2)
    Physics-Wave Optics-95782.png

  • Physics-Wave Optics-95783.png

  • Physics-Wave Optics-95784.png
Angular width of central maxima in the Fraunhoffer diffraction pattern of a slit is measured. The slit is illuminated by light of wavelength 6000 Å. When the slit is illuminated by light of another wavelength, the angular width decreases by 30%. The wavelength of this light will be
  • 6000 Å
  • 4200 Å
  • 3000 Å
  • 1800 Å
In a single slit diffraction experiment first minimum for red light (660 nm) coincides with first maximum of some other wavelength λ\' . The value of λ\' is
  • 4400 Å
  • 6600 Å
  • 2000 Å
  • 3500 Å
The ratio of intensities of consecutive maxima in the diffraction pattern due to a single slit is
  • 1 : 4 : 9
  • 1 : 2 : 3

  • Physics-Wave Optics-95788.png

  • Physics-Wave Optics-95789.png
Light is incident normally on a diffraction grating through which the first order diffraction is seen at 32°. The second order diffraction will be seen at
  • 48°
  • 64°
  • 80°
  • There is no second order diffraction in this case
White light may be considered to be a mixture of waves with λ ranging between 3900 Å and 7800 Å. An oil film of thickness 10,000 Å is examined normally by reflected light. If µ = 1.4 , then the film appears bright for
  • 4308 Å, 5091 Å, 6222 Å
  • 4000 Å, 5091 Å, 5600 Å
  • 4667 Å, 6222 Å, 7000 Å
  • 4000 Å, 4667 Å, 5600 Å, 7000 Å
Among the two interfering monochromatic sources A and B; A is ahead of B in phase by 66°. If the observation be taken from point P, such that PB – PA = λ/4. Then the phase difference between the waves from A and B reaching P is
  • 156°
  • 140°
  • 136°
  • 126°
A parallel plate capacitor of plate separation 2 mm is connected in an electric circuit having source voltage 400 V. If the plate area is 60 cm2, then the value of displacement current for 10–6s will be
  • 1.062 amp
  • 1.062 × 10–2 amp
  • 1.062 × 10–3 amp
  • 1.062 × 10–4 amp
A long straight wire of resistance R, radius a and length l carries a constant current I. The Pointing vector for the wire will be

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  • 2)
    Physics-Wave Optics-95796.png

  • Physics-Wave Optics-95797.png

  • Physics-Wave Optics-95798.png
In an electromagnetic wave, the amplitude of electric field is 1 V/m. The frequency of wave is 5 × 1014 Hz. The wave is propagating along z-axis. The average energy density of electric field, in Joule/m3, will be
  • 1.1 × 10–11
  • 2.2 × 10–12
  • 3.3 × 10–13
  • 4.4 × 10–14
A laser beam can be focussed on an area equal to the square of its wavelength. A He – Ne laser radiates energy at the rate of 1mW and its wavelength is 632.8 nm. The intensity of focussed beam will be
  • 1.5 × 1013 W/m2
  • 2.5 × 109 W/m2
  • 3.5 × 1017 W/m2
  • None of these
A lamp emits monochromatic green light uniformly in all directions. The lamp is 3% efficient in converting electrical power to electromagnetic waves and consumes 100W of power. The amplitude of the electric field associated with the electromagnetic radiation at a distance of 10m from the lamp will be
  • 1.34 V/m
  • 2.68 V/m
  • 5.36 V/m
  • 9.37 V/m
A wave is propagating in a medium of electric dielectric constant 2 and relative magnetic permeability 50. The wave impedance of such a medium is
  • 5 Ω
  • 376.6 Ω
  • 1883 Ω
  • 3776 Ω
A plane electromagnetic wave of wave intensity 6 W/m2 strikes a small mirror area 40 cm2, held perpendicular to the approaching wave. The momentum transferred by the wave to the mirror each second will be
  • 6.4 × 10–7 kg-m/s2
  • 4.8 × 10–8 kg-m/s2
  • 3.2 × 10–9 kg-m/s2
  • 1.6 ×10–10 kg-m/s2
A 20 cm length of a certain solution causes right handed rotation of 38°. A 30 cm length of another solution causes left handed rotation of 24°. The optical rotation caused by 30 cm length of a mixture of the above solution in the volume 1 : 2 is
  • Left handed rotation of 14°
  • Right handed rotation of 14°
  • Left handed rotation of 3°
  • Right handed rotation of 3°
A beam of natural light falls on a system of polaroids, which are arranged in succession such that each polaroid is turned through 30° with respect to the preceding one. The percentage of incident intensity that passes through the system will be
  • 100%
  • 50%
  • 30%
  • 12%
A beam of plane polarized light falls normally on a polarizer of cross sectional area 3 × 10–4m2. Flux of energy of incident ray in 10–3W. The polarizer rotates with an angular frequency of 31.4 rad/s. The energy of light passing through the polarizer per revolution will be
  • 10–4 Joule
  • 10–3 Joule
  • 10–2 Joule
  • 10–1 Joule
In a YDSE bi-chromatic light of wavelengths 400 nm and 560 nm used. The distance between the slit is 0.1 mm and the distance between the plane of the slits and the screen is lm. The minimum distance between two successive regions of complete darkness is
  • 4 mm
  • 5.6 mm
  • 14 mm
  • 28 mm
The maximum number of possible interference maxima for slit-separation equal to twice the wavelength in Young\'s double-slit experiment is
  • Infinite
  • Five
  • Three
  • Zero
The k line of singly ionised calcium has a wavelength of 393.3 nm as measured on earth. In the spectrum of one of the observed galaxies, this spectral line is located at 401.8 nm. The speed with which the galaxy is moving away from us, will be
  • 6480 km/s
  • 3240 km/s
  • 4240 km/s
  • None of the above
A Young\'s double slit experiment uses a monochromatic source. The shape of the interference fringes formed on a screen is
  • Straight line
  • Parabola
  • Hyperbola
  • Circle
If I0 is the intensity of the principle maximum in the single slit diffraction pattern, then what will be its intensity when the slit width is doubled

  • Physics-Wave Optics-95812.png
  • 2)
    Physics-Wave Optics-95813.png

  • Physics-Wave Optics-95814.png

  • Physics-Wave Optics-95815.png
In a Young\'s double slit experiment, the separation between the two slits is d and the wavelength of the light is λ The intensity of light falling on slit 1 is four times the intensity of light falling on slit 2. Choose the correct choice (s)
  • If d= λ, the screen will contain only maximum
  • If λ < d< 2 λ., at the least one more maximum (besides the central maximum) will be observed in the screen
  • If the intensity fo light falling on slit 1 is reduced so that it becomes equal to that of slit 2, the intensities of the observed dark and bright fringes will increase
  • If the intensity of light falling on slit 2 is increased so that it becomes equal to that of slit 1, the intensities of the observed dark and bright fringes will increase
In an interference arrangement similar to Young\'s double slit experiment, the slits S1 and S2 are illuminated with coherent microwave sources each of frequency 106 Hz. The sources are synchronized to have zero phase difference. The slits are separated by distance d= 150 m. The intensity I(θ) is measured as a function of θ, where θ is defined as shown. If I0 is maximum intensity, then I (θ) for 0 ≤ θ ≤ 90° is given by
Physics-Wave Optics-95817.png
  • I(θ) = I0 for θ = 0˚
  • I(θ) = I0/2 for θ = 30˚
  • I(θ) = I0/4 for θ = 90˚
  • I(θ) is constant for all values of θ
0:0:1


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